How rare is this Gucci Bowling bag???

Keep it if you love it but if it is not you and you prefer to get cash to use for something else you will definitely be able to sell it quickly for $1k+ as it is a rare collectible Gucci. Some similar to this have recently sold in the $1400s to $1600s, often more than the original retail. See the Blondie sticky thread for more info.
 
You shouldn't feel bad what ever you decide

1) your cousin gave it away

2) Now it's you bag so you must decide what you want to do

Take your time though coz it miht grow on you. :flowers: